Safety device for motion-picttrbe-pbojecting- machines



I 1,628,258 May 1 1927- w. MALM SAFETY DEVICE FOR MOTION PICTURE FROJECTING MACHINES Filed May 21. I925 IN V EN TOR.

Patented May 19, 1927.

UNITED STATES WILLIAM MALM, OF NEW OBLEAN S, LOUISIANA.

SAFETY DEVICE FOR MOTION-PICTURE-PROJECTING MACHINES.

Application filed May 21, 1925. Serial No. 81,870.

particularly to mechanism for eliminating.

the chief causes of film fires.

"In motion picture machines, as is well known, the motion pictur'e film "is passed across the apertureofthe projector, through which the projecting light-passes. Owing to the intensity of saidlight, projectors of the presentday type are provided with a shutter which automatically'cuts ofi said lightfrom the film, whensaid filni'is moved slowly enough to become ignited. -This shutter, however, is directly controlled by the speedof' the driving mechanism'of the to clutch shell 13, as'is lever-in Figure 2, "and is also loosely attached to lever 22by projector, and does'iiot protectthe'film from becoming ignited inin'stanc'es' where the film severed splices, or s'imilarffa-ultsfi v The obj ectof' my reseqt invention is to provide means operating automaticallyon the breaking of the film, the failure of the feed mechanism} or -"from any other cause of the film remaining stationary for an abbecomes at rest, dueto torn film-margins, I

' bracket 24' by pin said bracket being normal length of time, to cut off the light from the aperture, either by means of an auxiliary shutter or by an auxiliary switch automatically stopping the driving mechanism actuating the regular shutter.

A further object of my invention is to provide means for controlling said auxiliary shutter or auxiliary switchdirectly by the speed of the motion picture film as it passes the aperture, and not solely dependent upon the speed of the main driving mechanism of the machine, thereby protecting the film from igniting, irrespectlve of circumstances,

'and rendering the projector practically fire proof.

Other and ancillary objects of my invention will appear hereinafter.

In the accompanying drawings, Figure 1 is a side view of film passing over aperture plate of projector including my improved shutter and driving means therefor. F igure 2 is a plan view of shutter and driving means shown in Figure 1. Figure 3 is a plan view similar to Figure 2 with a slight modification, showing how the driving means may be made to actuate an auxiliary cut-oft switch in place of the shutter.

Referring to the drawings, Figures 1 to 3, inclusively, 1 is the sprocket wheel fixed on shaft 3, which intermittently feeds the film 3 past the aperture in plate 4. 5 is light 30 from film 3.

the upper feed sprocket, fixed on shaft 6, which maintains-loop in film 3.

7 is a bearing not shown in Figure 1, for simplicity supporting shaft 8 upon which is'fixed sprocket 9 and internal members It), 11, and 12, of friction clutchassembly comprised of said internal members and shell 13. Sprocket teeth 14 of sprocket 9 mesh with sprocket holes in film 3. Lever 15 is loosely attached on clutch shell 13 by pin 16. and is also loosely'attached toarm 17 of shutter 18 by pin 19. Said shutter 18 is supported by bearings QO-and 21, and cuts off Lever 15, in Figure 3, is loosely attached pin'-23'.--Lever 22 isr'loosely attached to fiXed-FonpIate 4'." Fixed onlever 22 is an 5 insulated contact plate-26 engaged with con tact spring 27 which is insulated and'fixed aonplat'e 41a? 52tiand' 27 comprise aswitch intended to be part of, and make and break the motor circuit of the projector.

While my invention has been illustrated in what is considered its best application, it may have other embodiments without departing from its spirit. It is not therefore, limited to the structures shown in the drawmgs.

The operation of the device will be obvious from the above description. The relation between shutter 18 and clutch shell 13 is such, that when film 3 is moved along plate 4 by sprocket 1, and like movement. is imparted to sprocket 9, centrifugal force causes members 10 and 11 (loosely attached to pins 28 and 29, respectively, which are fixed on plate 12) to rotate clutch shell 1 thereby lifting shutter 18. If for any reason whatsoever, the film 3 should become at rest at point of contact with sprocket. 9, due to torn film margins, severed splices or similar faults, then sprocket 9 will fail to rotate. thereby releasing clutch shell 13 and allowing shutter 18 to fall, thereby cutting oll' light 30 from film Figure 3 shows how similar movement of the clutch shell 13 actuated under conditions above described, can be made to open the circuit of the motor which drives the pro jector, thereby actuating the regular safety shutter found on the present day type of machines.

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\Vhat I claim as new and desire to secure by Letters Patent, is:

1. In a motion'picture machine, the combination with a motion picture film, of means for automatically protecting said film from ii -e, comprising an auto mati c light shutte actuated by a su'i'tableclut'ch 'device, said clutch device being driven by an auxiliary sprocket wheel, said sprocket wheel meshing with said film and moving in synchronism with said film and located at a suitable point between the intermittent driving sprocket and upper feed sprocketof said machine.

2. In a motion picture machine, the com bination with a motion picture film, of means for automatically protecting said film from fire, comprising an automatic safety shutter located at a point between source of projecting light and said film, and means for causin; said shutter to cut-off said light from said film whenever said film should become at rest in path of said light tor any abnormal length of time; comprising a suitable clutch device, said clutch device being driven by an auxiliary sprocket wheel, said sprocket wheel meshing with said 'film and movingin synchronism with said film and located at a suit-able point between the intermittent driying sprocket and upper feed sprocket 0i said machine.

3. In a motion picture machine, the combination with a motion picture film, of means tor automatically protecting said film from fire, comprising a suitably" located electric switch controlling motor circuit of said machine, said switch being actuated by means of a series of levers, and a suitable clutch device, said clutc device being driven by an auxiliary sprocket wheel, said sprocket wheel meshing with said film and moving in synchronism with said film and located at a suitable point between the intermittent driving sprocket and upper 'feed sprocket of said machine.

ln a motion picture machine, the combination with a motion picturclilm of means for automatically protecting said film from fire, comprising a suitably located electric switch controlling motor circuit of said machine, and means for causing said switch to cutoff motor circuit of said machine whenever said film should become at rest in path of projecting light for any a-bnormal length of time, comprising a suitable clutch e i e, said c u ch d i ei driwn y an auxiliary sprocket wheel, said sprocket h l me h ng it a d film an m g in synchronism with said film and located at a. suitable point between the intermittent vdriving sprocket and upper feed sprocket of said machine.

WIL IAM A 

